Boronic acid-decorated metal-organic frameworks modified via a mixed-ligand strategy for the selective enrichment of cis-diol containing nucleosides.

Functional metal-organic frameworks (MOFs) constructed via a pre-installation strategy of introducing mixed organic ligands have attracted considerable interest in various fields. In the present study, boronic acid decorated magnetic Zr-MOFs were successfully synthesized by introducing 3-carboxyphenylboronic acid ligands as fragments. The prepared material was used as an adsorbent for the enrichment of cis-diol-containing nucleosides. The adsorbent has excellent performance with regard to the enrichment and separation of the nucleosides. This may be attributed to its abundant boronic acid functional groups, and the convenience of magnetic separation it provides. The obtained material was chemically stable over a large pH range. The degree of linearity of the nucleosides was excellent (0.02-10 μg mL), and the detection and quantification limits were low (0.006-0.016 μg mL and 0.02-0.05 μg mL, respectively). Furthermore, it was possible to attain adsorption equilibrium within 10 min. The high efficiency of this method makes it suitable for the successful extraction of nucleosides from human urine samples, with satisfactory recoveries of 88-146%, and 1.7-9.4% precision. We believe that the fabricated functional magnetic MOFs have great potential for the analysis of other cis-diol-containing target, and the pre-installation strategy could be adapted for the wider application of MOFs.